Outer rotor type fan-motor

Abstract

An outer rotor type fan-motor includes: a rotational shaft; a bearing assembly that rotatably supports the rotational shaft; a stator installed at an outer side of the bearing assembly; a permanent magnet assembly that covers an outer side of the stator at a certain distance and is installed at the rotational shaft; and a fan that includes a shaft fixing part for fixing the rotational shaft, a hub for covering an outer side of the permanent magnet assembly at a certain distance and blades formed around the hub. An insulation space is formed between the permanent magnet assembly and the fan to prevent transfer of vibration and noise of the permanent magnet assembly to the fan, and vibration or noise of high frequency can be reduced.

1. An outer rotor type fan-motor comprising:
 a rotational shaft; 
 a stator installed at an outer side of the rotational shaft; 
 a permanent magnet assembly that covers an outer side of the stator at a certain distance and is installed at the rotational shaft; and 
 a fan, at which the rotational shaft is fixed, that is rotated together with the rotational shaft and includes a hub that covers an outer side of the permanent magnet assembly and blades formed on an outer surface of the hub, wherein an inner surface of the hub and an outer surface of the permanent magnet assembly are separated. 
 
     
     
       2. The fan motor of  claim 1  , wherein a step is formed along the circumference of a rotational shaft insertion hole formed to fix the rotational shaft on a portion of the inner surface of the hub where the rotational shaft is fixed, and the surface where the step is formed crosses the rotational shaft. 
     
     
       3. The fan motor of  claim 1 , wherein the fan comprises a shaft fixing part for fixing the rotational shaft, and a step is formed along a lengthwise direction of the rotational shaft on an inner surface of the shaft fixing part. 
     
     
       4. The fan motor of  claim 1  , wherein the permanent magnet assembly is formed as an elastic body for absorbing an electromagnetic exciting force generated through a space between the stator and the permanent magnet assembly. 
     
     
       5. The fan motor of  claim 1  , wherein a stopper for limiting an insertion depth of the rotational shaft is mounted at the shaft fixing part. 
     
     
       6. The fan motor of  claim 5 , wherein the stopper is integrally formed with the shaft fixing part. 
     
     
       7. The fan motor of  claim 1 , wherein a spring for maintaining a combining force between the fan and the rotational shaft is mounted on the outer surface of the shaft fixing part. 
     
     
       8. The fan motor of  claim 7 , wherein the spring has a cylindrical shape with a slit at one side thereof. 
     
     
       9. The fan motor of  claim 1 , wherein an adhesive is applied to the inner surface of the shaft fixing part in order to maintain the combining force between the fan and the rotational shaft. 
     
     
       10. The fan motor of  claim 1  , wherein a sound-absorbing member is installed on at least one of the outer surface of the permanent magnet assembly and the inner surface of the hub. 
     
     
       11. An outer rotor type fan-motor comprising:
 a rotational shaft; 
 a stator installed at an outer side of the rotational shaft; 
 a permanent magnet assembly that covers an outer side of the stator at a certain distance and is installed at the rotational shaft; and 
 a fan that includes a shaft fixing part for fixing the rotational shaft, a hub for covering an outer side of the permanent magnet assembly and blades formed on an outer surface of the hub, wherein an insulation space is formed between the permanent magnet assembly and the fan to reduce vibration or noise of the permanent magnet assembly from being transferred to the fan. 
 
     
     
       12. The fan motor of  claim 11  , wherein the permanent magnet assembly comprises: a cylindrical permanent magnet mounting part; and a disk-type shaft support part that covers one end of the permanent magnet mounting part. 
     
     
       13. The fan motor of  claim 12 , wherein a permanent magnet is mounted on an inner surface of the permanent magnet mounting part and separately installed at a certain distance from the stator. 
     
     
       14. The fan motor of  claim 12 , wherein a shaft through hole is formed at a central portion of the shaft support part, in which the rotational shaft is insertedly fixed, and a flange part is protrusively formed along the circumference of the shaft through hole. 
     
     
       15. The fan motor of  claim 14 , wherein the insulation space is formed between an outer surface of the permanent magnet mounting part and an inner surface of the hub and between the outer surface of the shaft support part and the inner surface of the hub. 
     
     
       16. The fan motor of  claim 15 , wherein the space between the outer surface of the shaft support part and the inner surface of the hub is smaller than the space between the outer surface of the permanent magnet mounting part and the inner surface of the hub. 
     
     
       17. The fan motor of  claim 14 , wherein a bearing assembly is installed between the rotational shaft and the stator in order to rotatably support the rotational shaft, and a bearing of the bearing assembly is an oilless bearing that does not need oil.